Recently, a demand for an electrical accident prevention system appropriate for electricity safety and a user facility environment in a U-city environment using a newly implemented ubiquitous technology, which is an advanced information communication technology, a space utilization technology has been increased.
The existing switch gear or low voltage distribution panel is a passive type. Recently, a technology in which the switch gear or the low voltage distribution panel is coupled with an electronic controller to measure quality of power and electric power and transmit the measured values in a digital form is being developed.
However, the existing distribution panel or switch gear does not include important components that measures and transmits risk factors of electricity safety and therefore, is inappropriate to apply to a U-city system that is to be coupled with IT technologies so as to improve convenience and safety of life.
Generally, a main factor of electrical fire among electrical accidents may include short circuit, overcurrent, arc, electrical short, and the like. Further, other main factors of electrical fire may further include facility environments (flooding, gas, temperature, outlet connection defect, and the like) of users.
In particular, unwarned outage and electrical accidents due to part defects, isolated deterioration, and the like, have been frequently caused in the existing switch gear. Due to this, there is no method for detecting arc and partial discharge in the switch gear so as to prevent outage and electrical accidents in the existing switch gear.
In addition, the distribution panel used in a house interrupts only a supply of electricity by an operation of a breaker mounted therein at the time of electrical short or overcurrent. Therefore, it is difficult to prevent fire because there are no facilities that can receive information regarding a safety state of the distribution panel, such as gas that may occur due to overload, overheat, and the like, in a breaker connection part, wirings, and the like, in the distribution panel, the connection defect of the outlet mounted in all the constructions such as a house, an apartment, a shopping mall, a building, and the like, and used electrical power, and the like.
Herein, as known, the distribution panel is a device that is again supplied with power from a switch board to open and close circuits in an electric system and distribute power into the house, which may be referred to as an interior distribution panel. Hereinafter, the switch board and the distribution panel are collectively referred to as the distribution panel.
Describing a circuit breaker mounted in the conventional distribution panel, the circuit breaker includes a microswitch mounted therein to transmit its own state.
FIG. 1 shows a three phase circuit breaker having a microswitch mounted therein for detecting a power supply state mounted in the conventional distribution panel. Referring to FIG. 1, the circuit breaker is provided with the micro switch.
Describing this in more detail, the conventional 3 phase circuit breaker having the microswitch mounted therein is operated by switching-on/off contacts of the microswitch using a mechanism therein.
In addition, the circuit breaker is further provided with a remote monitoring unit to transmit the operating state to managers in an external signal form, such that the managers can monitor the circuit breaker.
In other words, the microswitch generates an alarm signal indicating that a trip occurs due to an abnormal state of the circuit breaker and transmits the generated alarm signal to external managers to inform that the circuit breaker has been tripped.
However, in the case of the circuit breaker having a microswitch 10 mounted therein, it is difficult to mount the microswitch in a narrow space, costs are increased due to an increase in labor at the time of mounting the circuit breaker, and a contact loss may occur due to friction in a driving direction of the mechanism.
Further, since it is difficult to substantially mount the microswitch 10 in a small breaker such as a single phase branch breaker, there is no distribution panel having a function for accurately detecting a state of the branch breaker.
In addition, unlike the circuit breaker, it is substantially impossible to configure a distribution panel having microswitches for each branch breaker that is disposed en masse and a line facility transmitting a signal to the outside through the microswitches due to the increased costs and the mounting difficulty.
In addition, a distribution panel having a remote system to enable managers to remotely monitor arc, leakage current, overcurrent, overvoltage, and an on/off state of a breaker at all times has not yet been present.
Further, there is a need to measure AC voltage so as to enable a controller of the conventional distribution panel or the switch board system to monitor or measure power. Herein, the controller of the distribution panel or the switch board system is configured by a circuit isolated from a primary AC side for safety.
However, when an AC voltage measuring circuit or a sensing circuit of the primary side in the system controller is configured in a non-isolated form, the controller isolated from the AC power supply may be again non-isolated from the AC power supply for safety.
A representative example of a method for sensing the isolated AC voltage according to the related art may include a method for implementing isolation using a low-frequency transformer and dropping voltage to acquire a voltage value or a method for using a high-price dedicated semiconductor integrated circuit or dividing a magnitude in AC voltage into low voltage to read the low voltage by each processor. However, the method may increase a volume of a circuit, may degrade integration, and increase weight, which runs against a recent trend of a semiconductor in the electronic industry.
In the case of the related art, the AC voltage sensing circuit has been implemented by various methods. However, an AC voltage terminal is not electrically isolated from a DC voltage terminal.
In other words, when the AC voltage sensing circuit according to the related art uses the method for using a high-price dedicated semiconductor integrated circuit or dividing a magnitude in AC voltage into low voltage to read the low voltage by each processor, an output signal of the dedicated semiconductor integrated circuit and a driving power supply of each processor are commonly connected with a commercial power supply side that is a primary side and a ground. In order to use the read voltage signal as an alarm or a control signal in a secondary system such as various digital devices and the controller, the ground of the secondary side system needs to be also commonly connected therewith.
By this configuration, the primary side and the secondary side that is the ground of the system may not be isolated from each other.
Therefore, the non-isolated AC voltage sensing circuit according to the related art cannot be conveniently used by users in the state in which the digital devices or the controller are not electrically isolated from the AC voltage terminal and applications of the circuit, and the connection operation with other circuits, and the like, may not be easily implemented.
Further, the existing low voltage distribution panel is a passive type. However, recently, the low voltage distribution panel is coupled with an electronic controller to measure the voltage and electric power and display them.
However, the existing low voltage distribution panel does not have the important components for measuring and transmitting the risk factors necessary for the electricity safety. Therefore, when the distribution panel is damaged due to the electrical fire, it is difficult to analyze the fire factors.
In addition, when a current exceeding the rated current flows in the breaker mounted in the existing distribution panel, or the like, the breaker is bent due to a change in expansion coefficients of a bimetal mounted in the breaker to operate the driving contacts of the breaker, thereby interrupting the supply of power. Similarly, when the breaker is operated to interrupt instantaneous current when an inter-phase short accident such as a metal material, or the like, contacts the lower wiring and when the electrical short occurs, an unbalanced current is sensed by a zero current transformer (ZCT) to prevent a fire accident caused by such an electrical short or the electric shock.
However, even though the breaker is mounted, fire accidents caused by electricity frequently occur globally every year. The electrical fire and the electrical shock accidents frequently occur due to various factors such as defects due to arc, carbonization of the driving contacts of the breaker due to a continuous occurrence of electrical short, dielectric breakdown of wirings, an increase in mechanical and electrical stress of the wirings, a damage to the wirings due to overcurrent, defects of wiring connection, and the like.
That is, the existing breaker includes only a breaking component at the time of the occurrence of overcurrent or leakage current and does not include components for detecting the above problems and components for processing and transmitting data so as to enable managers of a remote server of the distribution panel or the switch gear to remotely receive, recognize, and monitor the detection data. Therefore, the above accidents may always happen.
In other words, in order for the managers to remotely recognize signals from the detection sensors included in the breaker, the data needs to be processed. In order to for the breaker to include components to process the data, the distribution panel or the switch gear needs to be configured so that they are wire-connected with the detection sensors included in each of the plurality of breakers. However, it is difficult to mount the detection sensors therein or really maintain and manage the detection sensors.
In addition, it is difficult to really configure the distribution panel while outputting signals by connecting with each of the branch breaker in a wired form in the state in which the small breaker such as the branch breaker of the distribution panel is disposed en masse.
Meanwhile, the electrical fire due to the contact defects has a lower frequency than the electrical fire due to other factors and thus, a technology development of detecting the contact defects has not been actively conducted. As a result, there is no technology for the prevention of the fire due to the contact defects. However, most of the electrical fires due to the contact defects are determined as other factors due to a difficulty in inspecting the electrical fires, which have low statistics. Therefore, the frequency of accidents due to the contact defects is estimated to be higher than the statistics.
In order to reduce the risk of electrical fire, electrical signal features of the contact defects are extracted. Based on the extracted features, the electrical fire can be prevented by taking prompt actions on electric facilities that may have greater risk of electrical fires.
Therefore, a need exists for a system of securing objective and scientific data by three-dimensional simulation and experiments for the contact defects and collecting symptoms of electrical fires based on the secured data to take appropriate actions.